The present invention relates to distillation apparatus, and method.
Distillation apparatus has been provided for many years, particularly for providing improved quality of water, such as water for drinking. Such distillation apparatus has typically taken the form of a feed water pre-heater which is connected to an evaporator tank. The evaporator tank has a heater, such as an electric heater, which causes the water to boil. The resulting steam is passed through the pre-heater, where it is condensed, imparting heat to the feed water, and raising the temperature of the feed water. The evaporation of water in the evaporator tank generates steam which is pure, with a resulting increasing concentration of the dissolved matters contained in the water in the evaporator tank, thus leading to the buildup of scale. Scale buildup is undesirable, and leads to such undesirable effects as coating of various parts of the apparatus, including the small passages, leading to a closing off of some passages as the scale buildup continues.
The problem of scale buildup has been recognized in the prior art. Skow, U.S. Pat. No. 3,055,810 provides for the continuous drain of water from the evaporator tank, to some waste discharge, such as a sewer. This is a wasteful procedure, and is particularly undesirable where the supply of water is either limited, or expensive, or both, and energy is expensive.
Another recognition of the problem in the prior art is provided in Kirschmann, U.S. Pat. No. 3,980,526, wherein rods are provided in small passageways, with mean to vibrate the rods, so as to attempt to provide a mechanical vibration or abrasion in the passages, so as to remove scale as it is built up.
Another problem with water distillation apparatus has been that the temperature of the condensate, or condensed steam, has been undesirably high. In Skow, U.S. Pat. No. 3,055,810, a refrigeration apparatus was provided in the storage tank, which received the condensed steam, in order to lower the temperature to the desired degree, as for drinking.